Process of producing and protecting insulating-coverings of oxid on wires, bands, &amp;c.



UNITED STATES PATENT OFFICE.

ERNST WOLFGANG KUTTN'ER, OF BERLIN, GERMANY.

PROCESS OF PRODUCING AND PROTECTING INSULATING-'COVERINGS OF OXID ON WIRES, BANDS, &0.

No Drawing.

To all whom it may concern Be it known that I, Dr. ERNST WonrcAN Kr'i'rrNnn, engineer, citizen of Germany, subject of the King of Prumia and Emperor of Germany, residing at Berlin, in the Kingdom of Prussia and Empire of Germany, have invented new and useful improvements in processes of producing and protecting insulating coverings of oxid on wires, bands, bundles, or coils, particularly of aluminium and its alloys, of which the following is a specification. g

It is known that on naked metallic wires and bands a covering of oxid can be produced, which serves in many instancesas a sufiicient electric insulation. On aluminium wires a well insulating covering of oxid will form by itself. But the insulation obtained by such means is not uniform and durable, particularly if the oxidized wires are subse quently to be Wound into coils. For the purpose of producing coverings of oxid on naked metallic wires or bands, particularly such of greater section, which are intended to be wound in coils or solenoids, an oxidizing medium is made to act in such a manner that a close contact is obtained between the said oxidizingmedium and all parts of the.

metallic surface. This process is to be particularly employed for aluminium and its alloys. The completed coil wound of naked wire may also be exposed to the action of the oxidizing medium. Instead of oxids the insulating layers may consist of other chemical compounds (as for instance salts) of themetal.

The coveringsof oxid, hydroxid or salt produced by one of the hereinbefore de-. scribed methods are still very easily affected by friction or pressure or the like.

With the object of protecting them against the effects of prmre during their finishing process, transport and installation and use the present invention provides that a suitable protective coating is brought upon such treated metallic surface. With coils such protective coating or. filling is introduced into the interior of the coils and between the individual turns. This covering may according to circumstances be arranged only after the coils have. been completed and even after theyhave been bound (bandaged). In doing so it will be preferable to employ a vacuum or a. pressure, so as to allow of the filling material penetrating more deeply Patented May 4, 1915.

Application filed September 2, 1910. Serial No. 580,196.

through the bandages into the interior of the coil. In most instances it will, however, be advisable, to introduce the filling into the coil before the latter is bound, as the filling w1ll then also help to compensate or render harmless the frictional pressure produced in binding. If a suitable protecting medium is employed, the coils may be also treated with 1t already during the oxidizing process. Preferably the filling may consist of a liquid, WhlCll Wlll, after cooling or by evaporation, become sufiiciently solid and dry. So a material which will melt under the influence of heat, as wax, resin, pitch, india-rubber or thelike may be introduced into a coil heated to a sufficiently high temperature. For the purpose of obtaining a thorough penetration a vacuum or an overpressure ma be employed. In many instances it will su cc to simply dipthe coil into the molten medium. On the other hand a solution in alcohol or benzin or the like may be employed, such as varnish, rubber-solution or the like. .Also these may be introduced into the coils by a dipping process, either in a cold or hot state or by impregnation either in a vacuum or under pressure. In the last mentioned instance the drying and evaporation of the solvent may be accelerated by heating. On thecoils being heated, a better distribution or enetration of many mediums will be obtain and for the purpose of improving this eii'ect the finished or half finished coils may be heated either once or several times. Such. protective mediums may, provided they pliable or soft also be applied to the oxidized wires before the same are wound into coils; in such instance the wires will be oxidized in their raw state say in bundles or rings and are wound into coils while being simultaneously provided with the soft protective covering. It obvious, that the filling medium should then be tough and adhesive, so that itis not squeezed out by the winding operation and will not flake off.

If a substance is employed as protective medium, which will have an oxidizing effeet on the metal, the covering of oxid may be .further increased by the action of the protective'medium. As such protective medium may be employed oxidizing varnishes,

which are varnishes having an acid or alkalic reaction. For instance, such often occurs in .the trade oil varnishes containing free oleic acid or prepared with rancid oils. These varnishes are ordinarily avoided in the treatment of metals, as they attack them, 1

instance, oil colors prepared with rancid- 'oils. Also varnishes or paints of an otherwise neutral character may be converted into an oxidizing medium, by adding to them an oxidizing substance or applying such oxi-- dizing substance to the surface of the wires i may thereby mix with'the protective me? besides the paint. The coils or wires may be treated with an oxidizing liquid or an oxidizing vapor and, be covered while still moist with the protective covering, so that the oxidizing medium will for some time still ,continue' its oxidizing-efi'ect under'the protective covermg. The oxidizing'medium dium. If an aluminium wire or coil is moistened' with water and then saturated with any varnish, preferably at a raised temper- ,ature, a coverin of 01nd will be. gradually I produced and wi increase in thickness until the water will have disappeared beneath the coat of varnish, which may be preferably obtained by artificial drying.

fill out the coils; itiwill, in many instances be quite sufiicient if the outer turns are penetrated by the subsequently hardening protective medium, so that. a sort of crust is formed, which will receive the outside ressure and distribute it over-larger suracesof the coil It is not absolutely necessary, for the protective covering to consist of an insulating material, as the insulation proper of the wires is produced by the cov- I ering of oxid' and the filling medium has the v object only to afford a mechanical protection for the covering of oxid. p

Having now particularly described and ascertained the nature of my saidinvention, and in what manner the same is to be a performed, I declare that what I claim is:

1. A rocess for producing electric coils comprislng the steps of winding a wire containing aluminum and of any shape into coils, oxidizing the entire surface of said wire after it is coiled, and covering the .oxidized surface with a mechanically resistant coating adapted to protect said oxidized surface against the damages of pressure.

2-. A process for producing electric coils comprising the steps of winding'into coils a wire containing aluminum and of any shape,- oxidizing the entire surface of said wire after it is coiled and covering the oxidized surface with a mechanically resistant coating adapted to protect said oxidized surface.

theinterior of the coil vidual turns;

3.- A process for producing electric coils comprislng the steps of windmg into coils a wire containing aluminum and of any shape,

nd betteen the mar oxidizing the entire surface of said wire,

4, A process for producing electric coils comprising the steps of'winding a wire containing aluminum and of any shape into coils, oxidizing the entire surface of said wire after .it is coiled, and covering the oxidized surface with a mechanically resistant coating adapted to protect said oxidized surface against the damages of pressure,

saidcoating consisting of a solution with an evaporable solvent, said coating being introduced in a liquid state into the interior of the coil and between the individual, turns.

5. A process for producing and protecting insulating coverings of mid on metallic wires' of. any shape. containing aluminum 'and in the form of bundl$ or, coils, which I j consists in oxidizing the entire surface and The protective covering need not entirely v times.

' 6; A process for producing and protecting insulating coverings of ox1d on wires, or

alloys, which consists in treating thefsurdifylng and dryingprotective liquid, said liquid; being intro-- bands, particularly of aluminum and its face of the metal in all parts with an oxidizingmedium, the oxid produced. being Y protected by "a coating consisting of a liquid which will become sufiiciently solid and dry before the insulating wires areexposed to friction or pressure, said coating having oxidizing properties, while it still remains liqruid.

A process for producing and protecting insulating coverings of 0nd on wires or bands particularly of aluminum and its alloys, which consists in treating the surface of the metal 'in all parts with .a solidifying and drying liquid having oxidizing properties and which on becoming sufiiciently solid and dry forms a protective coating on the oxidized metallic surface before the wires are exposed to friction or pressure.

8-. A process for producing and protect I ing insulating coverings of 0nd on wires, bands, bundles or coils, particularly of aluminum and its alloys consisting in treating the surface of the metal in all'parts with an oxidizing medium, a protective coating being applied to said metallic surfaces while the oxidizing medium on said metallic surfaces is yet active, the said protective coating and the oxidizing medium being both applied in a moist state.

9. A process for producing and protecting insulating coverings of oxid on Wires, bands, bundles or coils, particularly of aluminum and its alloys, consisting in treating the surface of the metal in all parts with an oxidizing medium, a protective coating being applied to said metallic surface while the oxidizing medium on said metallic surface is yet active, the said protective coating and the oxidizing medium being both applied in a moist state and accelerating the drying process by heating.

10. A process for producing and protect- KUTTNER. 

